Field of the Invention
The present invention relates to a solid-state imaging device including an AD converter.
Description of the Related Art
There is a technology in the field of solid-state imaging devices, in which an analog-to-digital converter (hereinafter referred to as AD converter) is arranged in each column of pixels in an array-like arrangement and a signal from each pixel is converted into digital data. In Japanese Patent Application Laid-Open No. 2000-286706, there is disclosed a technology in which an inverter is used for a comparator circuit included in each AD converter.
In the technology disclosed in Japanese Patent Application Laid-Open No. 2000-286706, a signal from a pixel is input to a sampling capacitor during sampling, and a reference signal is input to an inverter via the sampling capacitor during AD conversion. Digital data is acquired through storing a time at which an output potential of the inverter is inverted to perform the AD conversion.
However, in the technology described in Japanese Patent Application Laid-Open No. 2000-286706, the conversion range of the AD conversion is limited by a range of voltage that can be input to the inverter. In other words, the upper and lower limits of the potential of the reference signal are limited by the range of voltage that can be input to the inverter, and thus, it is difficult to realize a high S/N ratio. Further, in order to increase the range of voltage that can be input to the inverter, it is necessary to increase a power supply voltage, which increases power consumption.